The fabrication of large structures may involve the performance of a large number of manufacturing operations on the structure, such as the drilling of a large number of holes. Conventional structures that require a large number of manufacturing operations include, for example, aircraft, missiles, ships, railcars, sheet metal buildings, and other similar structures. In particular, conventional aircraft fabrication processes typically involve the drilling of a large number of holes in fuselage sections of the aircraft to allow these sections to be attached to each other and to the airframe.
A variety of devices have been developed to facilitate drilling operations involving the drilling of a large number of holes. For example, U.S. Pat. No. 4,850,763 issued to Jack et al. teaches a drilling system that includes a pair of rails temporarily attached to an aircraft fuselage. A support carriage is slideably coupled to the rails and supports a drill assembly. A template attached to the aircraft fuselage provides an indication of the desired locations of the holes that are to be formed in the aircraft fuselage. As the carriage is moved along the rails, a locking mechanism (or trigger) interacts with the template to securely position the carriage for a subsequent drilling operation.
Although desirable results have been achieved using prior art systems, there is room for improvement. For example, the ability to accurately position a manufacturing tool over a workpiece may be compromised when the structure is contoured. This is particularly true when the structure is a complex contoured structure that is curved in multiple planes of curvature. Because position accuracy may be reduced, manufacturing operations on such structures may require increased delays due to a need for increased checking and adjusting of the position of the manufacturing tool, and may also require additional repairs and reworking of the workpiece due to inaccuracies in the manufacturing operations. Thus, the foregoing reasons, an unmet need exists for an improved support assembly for performing manufacturing operations, including drilling operations.